Heatless blood vessel harvesting device

ABSTRACT

A method and device are disclosed directed at harvesting of vessels, such as arteries and veins, especially as required in vessel grafting procedures. The device and method discloses a cannula-like device that provides, identification, capture, manipulation, hemostasis and cleavage of branch vessels from the harvested vessel without need for further devices. In certain preferred embodiments of the disclosed method and device, the disclosed harvesting device achieves branch vessel cleavage and hemostasis without the use of heat producing means such as cautery. In addition, certain embodiments utilize a clip/coil magazine technology so as to enable severance and hemostasis of multiple branch vessels without need for removal of the device from the surgical site. Further embodiments disclose the incorporation and use of irrigants containing CO2, as well as other agents capable of stimulate release of nitric oxide from vascular endothelium are applied to subject vessels so as to enhance the viability of vessels to be harvested as graft material.

This application is a divisional application of U.S. patent applicationSer. No. 10/988,931 filed Nov. 15, 2004 which is hereby incorporated byreference.

TECHNICAL FIELD

The present invention is related to devices and methods of utilizingsuch devices for harvesting blood vessels. More specifically, thepresent invention is directed at a device and method particularly usefulin separating a desired artery or vein from lateral branch vessels so asto allow excision of such for use as, for example, a graft,—withoutgeneration of vessel damaging heat—.

BACKGROUND OF THE INVENTION

It is a fairly common procedure to utilize viable healthy blood vesselsfrom one part of a patient's circulatory system as a graft in order toreplace a blocked, damaged or diseased vessel at another location. Forexample, the coronary arteries are especially prone and subject toatherosclerosis as well as other vessel damaging and occluding diseases.Coronary bypass surgery commonly utilizes healthy segments of the radialartery, saphenous vein and other blood vessels as grafts to replace suchdiseased vessels.

In order to obtain a suitable length of a given artery or vein for useas a graft, a harvesting procedure in which a surgeon excises a desiredlength of donor vessel must first be accomplished. In accomplishing suchharvesting procedures, the selected donor vessel must be safelyseparated from lateral (or branch) vessels arising from the main vesselto be harvested. Also, the donor vessel must be cleaved, at a proximaland distal point from them main vessel from which it arises in order tofully free the segment for use as a graft.

Harvesting procedures involve obtaining access to the donor vessel. Inthe past, such access has been accomplished with lengthy skin incisionsmade along the length of vessel to be harvested. Thereafter, bluntdissection of the vessel from connective tissue, fat and otherstructures adherent upon it, followed by cleavage of branch vessels wascommonly performed. Recently, endoscopic approaches have been utilizedto harvest vessels. Such procedures typically commence with small skinincisions made at locations in close proximity to the proximal anddistal extent of the graft desired. Thereafter, an endoscope is utilizedalong with instruments, especially designed for endoscopic surgery, toaccomplish blunt dissection and severing of the vessel from lateralbranches. Such techniques are far more conservative in nature andinvolve substantially reduced skin incisions—and concomitant prolongedhealing and pain—as compared to open techniques. However, the relativelysmall enclosed field in which multiple instruments must be utilizedmakes the procedure somewhat less than ideal. U.S. Pat. No. 5,899,912,Eaves III (the “'912 patent”) discloses a harvesting apparatus utilizedin endoscopic removal of blood vessels. The disclosed harvestinginstrument includes a harvesting head with a channel for receiving ablood vessel as well as at least one slot extending from the channel tothe outer surface of the harvesting head for receipt of side branches ofthe vessel. The slot contains a blade for severing side branches andelectro cautery for sealing the cut ends of the vessel. The outsidesurface of the harvesting head may be utilized for blunt dissectionabout the vessel to be harvested. Although the '912 patent discloses aharvesting instrument which provides blunt dissection as well ascleavage and sealing of side branches, the device does not provide anymeans of operator control or guidance of the position of vessels withinthe harvesting head save through the gross manipulation of a handledepending from the harvesting head. Also, no means is disclosed forretaining a vessel within the instrument during the cutting/cauteryprocedure.

SUMMARY OF THE INVENTION

Now in accordance with the present invention, a blood vessel harvestingdevice is disclosed. The harvesting device of the present invention iscomprised of a harvesting cannula generally configured as an elongated,hollow tube having a longitudinal axis. The cannula includes an outerwall, a central bore, a proximal and a distal terminus. The cannula iscomprised of three sections: a harvesting head, a tubular controlsegment and a sliding operation arm. The tubular control segment andharvesting head are contiguous structures which form a portion of thehollow, tubular cannula structure discussed above.

The tubular control segment is located and forms, in combination with aproximal portion of the sliding operation arm, the proximal portion ofthe harvesting cannula. The control segment joins distally and iscontinuous with the harvesting head which is located at the distal endof the cannula. The sliding operation arm is slidably affixed andcompletes a superior portion of the outer walls of both the controlsegment and harvesting head. The outer walls of the harvesting head,tubular control segment, and sliding operation arm define the elongated,hollow harvesting cannula and surround, so as to form the central borethere within.

As mentioned above, when positioned in a forward (or fore) position, thedistal terminus of the sliding operation arm comes into contact with andcompletes a superior aspect of the distal portion of the outer wall ofthe harvesting head. When positioned in a rearward or aft position, aspace is formed between the harvesting head and sliding operation arm soas to form the lateral branch capture notch, discussed below. Therefore,in the fore position, the sliding operation arm provides completion ofthe outer cannula walls save for the main vessel alignment slot,discussed below. The term “aft”, as utilized throughout thisspecification and in the claims is a directional term which refers tothe proximal end of the cannula. Thus, the term “aft direction” meanstowards the proximal end of the cannula. The term “fore”, as utilizedthroughout this specification and in the claims is a directional termreferring to the refers to the distal end of the cannula. Thus the term“fore direction” means towards the distal end of the cannula.

The harvesting head, located at and forming the distal portion of thecannula includes a central bore, proximal and distal terminus, and maybe described as including superior and inferior portions. The harvestinghead may advantageously include an opening (or “distal aperture”) at thedistal terminus thereof (which is also the distal terminus of the entiredevice). The distal aperture is contiguous with the central bore of thecannula.

The outer wall of the harvesting head is interrupted by a main vesselalignment slot penetrating through the outer wall of both the harvestinghead and the distal portion of the sliding operation arm (which, in afore position, completes the proximal extent of the superior outer wallof the harvesting head). The alignment slot communicates freely with thecentral bore. The main vessel alignment slot may be advantageouslyconfigured at an angular (non-parallel) relation with the longitudinalaxis of the cannula so as to assist vessel retention as discussed below.The slot extends from the distal terminus of the cannula (distalterminus of the harvesting head) proximally and terminates in theproximal/superior portion of the outer wall of the harvesting headcompleted by the sliding operation arm.

The specific width and length of the main vessel alignment slot isconfigured so as to provide—as discussed below—efficient capture andretention of vessels to be harvested. Retention of the vessel to beharvested is aided by both the skewed position of the main alignmentslot—in embodiments incorporating such configuration—as well asengagement of the vessel by the vessel capture and manipulation meansor, in certain alternative embodiments, the main vessel retentiongate(s), discussed below.

In preferred embodiments of the present invention, the distal portion ofthe cannula comprising the harvesting head exhibits a greater diameterrelative to the remainder of the cannula. Increased diameter provides anincreased central bore area for accommodating branch arteries,increasing the operative field thereby enhancing visualization of theprocedure and providing more area for manipulation of vessels (asdiscussed below). Also, in certain preferred embodiments of the presentinvention, the harvesting head may be advantageously shaped andconfigured in an elliptical (or “egg shape”) with tapered proximal anddistal termini in order to aid blunt dissection about the vessel to beharvested. In addition to the increased visualization provided by theenlarged central bore of the harvesting head, it is preferred thatembodiments of the present invention are comprised of a biocompatibletransparent material such as, for example a plastic material so as tofurther enhance visualization of the operative field. It is alsopreferred that the material of which the cannula is comprised isnon-conduction so as to facilitate safe use of electro and radiosurgical instruments as described herein.

The proximal portion of the cannula—the tubular control segment—providesa means of positioning the harvesting head (e.g. a handle) as well as aconduit for passage of various linkages, tubes and wires to the distalend of the instrument. Therefore certain preferred embodiments of thepresent invention may advantageously include a plurality of apertures atthe proximal terminus and/or channels through the outer wall of thecontrol segment so as to provide access for instrument control cables,rods, lines and linkages in order to provide, for example: irrigation,with or without CO₂ aspiration; endoscopic cameras, lighting and thebelow described vessel capture/manipulation means. Such cables, lines,rods and linkages may, as described below, be positioned within thecentral bore of the cannula or be housed within channels located withinthe outer walls thereof.

The outer wall of the harvesting head includes, in addition to the mainvessel alignment slot, at least one branch vessel capture notchpenetrating through to the central bore. The at least one branch vesselcapture notch is positioned so as to extend laterally from the mainvessel alignment slot near to the proximal extent and portion of themain alignment slot. The branch vessel capture notch can also bedescribed as running, from a distal portion of the main alignment slot,in a generally circumferential direction about the longitudinal axis ofthe cannula along the outer wall of the harvesting head. The capturenotch freely communicates with the vessel alignment slot as well as thecentral bore of the harvesting head. Positioning the branch vesselcapture notch(es) adjacent the distal portion of the alignment slotenhances the effect of biasing forces, applied by vessel retentionmeans, which assist guidance and seating of branch vessels within thecapture notch(es) (discussed below).

In the first preferred embodiment of the present invention, the capturenotch(es) is defined and formed between edges of the outer walls of thesliding operation arm and harvesting head. For example the capture notchmay be formed by and between 1. an edge of the outer wall comprising thedistal terminus of the sliding operation arm; and 2. an adjacent edge ofthe outer wall of a superior portion of the harvesting head adjacent tothe distal terminus of the sliding operation arm. In a “closed” positionin which the sliding operation arm is in a “fore” position, theseadjacent edges of the sliding operation arm and harvesting head are incontact and, in fact, the distal portion of the sliding operation armcompletes the superior aspect of the harvesting head in such aconfiguration. In an “open” position, a space or “notch” forms betweenthe afore-mentioned superior portion of the harvesting head and slidingoperation arm so as to form the capture notch(es). More specifically, inan “aft” position, the sliding operation arm is moved backwards by asurgeon, so as to leave a gap between the outer wall (and the edges ofthe walls defining the termini thereof) of the sliding operation arm andthe edge of the outer wall of the harvesting head ordinarily adjacentand in opposition thereto. This gap—the branch vessel capture notch—isadvantageously utilized in preferred embodiments of the presentinvention to capture, apply hemostasis to, and sever branch vessels fromthe segment of the vessel to be harvested. The opposing edges of theouter wall of the harvesting head and sliding operation arm forming thecapture notches may converge, to a slight extent, distally, in order theenhance positioning of a lateral vessel in proper alignment withcautery, cutting and/clipping means. In preferred embodiments of thepresent invention, the at least one branch vessel capture notchcommunicates with the main vessel alignment groove proximate to thegrooves proximal terminus.

The afore-mentioned edges of the outer wall defining the at least onevessel capture notch of the present invention include a means forsevering branch (also referred to as “lateral”) vessels from the vesselto be harvested. The means for severing branch vessels may be selectedto be, for example, bi-polar or uni-polar electro surgery cuttinginstruments (also referred to as electro or radio surgery/cautery“tips”), laser cutting instruments, harmonic instruments or cold steel(edged instruments). In addition, the notches may also be provided withelectro-cautery means so as to enable coagulation (and hemostasis) ofsuch branch vessels. The notches may also be equipped so as to applysurgical clips or coils such as, for example Nitinol™ coils to vesselsso as to avoid the creation of potentially injurious heat duringcauterization. Thus, the device of the present invention contemplates,in certain preferred embodiments, 1. coagulating branch arteries bymeans of, for example, the use of electro surgery tips applyingcoagulating current; 2. applying surgical clips or coils to mechanicallyocclude branch vessels; 3. severing such branch arteries by means ofelectro surgery tips applying cutting current, laser means, ultrasonicmeans and cold steel for severing branch vessels; and 4. utilizing bothcoagulation (for hemostasis) or surgical clips/coils and cutting means.

In embodiments of the present invention wherein the at least one vesselcapture notch is provided with both electro cautery (or coils/clips) forhemostasis as well as a severing means (such as electro surgical tipsutilizing a cutting current, a laser means, harmonic means or coldsteel), it is highly advantageous to position, for example, coagulatingelectro cautery tips (or coils) at two points along the branch vesselcapture notch located on either side of the cutting means. In this way,as discussed in further detail below, branch vessels captured within thenotch(es) may be coagulated or mechanically crimped (so as to providehemostasis) on either side of the point at which the vessel is severedthereby reducing or eliminating blood loss during branch vessel release.In those preferred embodiments of the present invention wherein clipsand/or surgical coils are utilized to occlude branch vessels, it isespecially advantageous to configure such harvesters so as to include aclip/coil cartridge, or, as it may also be described, a clip/coilmagazine. The use of such cartridges/magazines enables the harvester ofthe present invention to apply vessel occluding devices such as, forexample, surgical clips and surgical coils to a plurality of branchvessels encountered during surgery without the need for removing theharvesting device from the surgical site (from the vessel to beharvested) for clip or coil reloading.

The terms “cartridge” and “magazine”, as utilized throughout thisspecification and within the claims, are interchangeable and equivalentterms and refer to devices utilized for storage and delivery of aplurality of clips and/or coils. Such magazines are ordinarily, asdescribed below, removable from and contained within the tubular controlsegment of the cannula. Such devices are more specifically describedbelow within the detailed description. It is preferred that the deviceof the present invention includes two branch vessel capture notcheslocated lateral to, and on opposite sides of the main vessel alignmentslot. The branch vessel capture notch(es) are advantageously positioned,for example, lateral to the alignment slot, between the below describedmain vessel capturing means and the distal terminus of the slot. Suchpositioning, as discussed below, improves the ease with which the devicemay engage vessels to be harvested while taking advantage of the biasingforce provided by the main vessel capturing and manipulation means(discussed below) and/or main vessel capture gate utilized to guide thebranch vessels into the capture notches.

It is highly advantageous, in certain preferred embodiments of thepresent invention, to configure the harvesting cannula so as to include,at an inferior portion thereof, a concave segment of outer wall locatedgenerally opposite the main vessel alignment slot—bulging outward, awayfrom the central slot—so as to provide, as discussed in more detailbelow, adequate room within the central bore for branch vessels arisingfrom a posterior portion of the vessel to be harvested. Such aconfiguration allows the cannula to pass along the main vessel andengage lateral branch arteries, without being stopped or hindered byposterior branches. After severing lateral branches in the vicinity ofsuch bulges, the main vessel capture/manipulation means may be utilizedwith or without rotation of the entire cannula, so as to allow the atleast one capture notch to engage and then sever such posteriorbranches.

The harvesting cannula of the present invention includes a means forretaining the vessel to be harvested within the harvesting head—separateand apart, for example, from the skewed configuration of the main vesselalignment slot—discussed above. The retaining means provides twofunctions. Firstly, the retaining means acts to simply maintain the mainvessel within the confines of the central bore of the harvesting head.Secondly, the retaining means creates a biasing force that assists thesurgeon in capturing and positioning branch vessels within the branchvessel capture notches. If the retaining means is, in fact, a captureand manipulation means, then a third function, enhanced manipulation ofside branches into the capture notch(es), is provided.

In a first preferred embodiment of the present invention, a main vesselcapture and manipulation means is provided so as to allow capture andretention of a vessel to be harvested within the central bore of theharvesting head; and 2. manipulation of the vessel in lateral, superiorand inferior directions so as to assist positioning of branch vesselswithin branch vessel capture notches. The main vessel capture andmanipulation means may be advantageously comprised of, for example, acontrol rod running through the control segment and/or sliding operationarm to the central bore of the harvesting head. A proximal terminus ofthe control rod is linked to a control means enabling an operator torotate and, in certain preferred embodiments, control fore/aft movementof a distal, vessel engaging terminus of the rod. For example, thedistal terminus of the control rod may be advantageously configured toinclude, for example, a “V” or “L” shaped bend for vessel entrapment andcontrol of movement. In certain other preferred embodiments, the distalterminus of the control rod may include a coiled configuration. Forexample, a “pig tail” may be provided at the distal terminus of thecontrol rod so as to allow capture and manipulation of a vessel to beharvested. The vessel engaging terminus is positioned so as to allow andprovide capture of the main vessel in close proximity to the proximalterminus of the main vessel alignment slot. For example, the engagingterminus may be advantageously positioned just proximal to the branchvessel capture notches. Such positioning allows the control rod to applysufficient downward (towards the inferior surface of the cannula andharvesting head) biasing forces upon a main vessel captured within thecentral bore so as to cause branch arteries to drop into the capturenotches. Therefore, in the first preferred embodiment of the presentinvention, the harvesting cannula incorporates a vesselcapture/manipulation means in order to provide a surgeon with a means ofcontrolling the lateral as well as superior/inferior position of avessel to be harvested—and the branch vessels thereof—so as to enable:a. capture and retention of a portion of the main vessel within thecentral bore of the cannula; and 2. manipulation of the vessel so as toguide branch (lateral and posterior) vessels into capture notches forseverance and hemostasis (coagulation/surgical clip) procedures. Forexample, in embodiment of the present invention wherein the capture andretention means comprises a control rod, the distal terminus (the vesselengagement configuration) may be configured as an open coil. In suchconfiguration a proximal control means such as, for example, a slidingdial, may be used to advance the coil towards the main vessel, rotatethe coil to an open position to engage the vessel, and then furtherrotate the coil for vessel capture. Thereafter the control rod isutilized to manipulate the main vessel (the vessel to be harvested) insuch a manner as to cause branch vessels to enter and be properlypositioned within the branch vessel capture notches. The term “properlypositioned” as used herein in regard to control rod manipulation ofbranch vessels refers to placement of the branch vessels at a positionwithin the slot notches wherein the vessel is aligned with vesselcoagulation means, cutting means and/or clip application means.

In a second preferred embodiment of the present invention, the mainvessel retaining means comprises a retention gate positioned just distalto the proximal terminus of the main vessel alignment slot. The manretention gate is positioned a sufficient distance, as described below,so as to allow enough clearance for the main vessel to exit the cannulabetween the gate(s) and the proximal slot terminus. The retention gatemay be comprised of one gate or two gates which are operably positionedin either 1. an “open” position leaving the main alignment slotunobstructed for initial vessel capture and 2. a closed position whereinthe gate(s) breach the width of the main alignment slot, just forward(fore) of the distal terminus thereof so as to allow capture of a vesselto be harvested within the device. As in the case of the vesselcapture/manipulation means, the retention gate, positioned just forwardof a vessel exiting the cannula (at the proximal terminus of thealignment slot) creates a biasing force so as to urge the main vessel(as branch vessels attached thereto) downward, thereby aiding capture oflateral vessels within the capture notches.

The harvesting cannula of the present invention also advantageouslyincludes, or provided means for including an endoscopic camera withinthe confines thereof for visualizing the vessel to be harvested as wellas the afore-mentioned manipulation/coagulation and cutting of branchvessels. In addition, certain preferred embodiments of the presentinvention incorporate a means for irrigating the operative field with,for example, saline solution and CO2 within the cannula. Such irrigationmay be provided by delivery lines entering the proximal terminus ofcannula through various apertures. These lines may run, for example,through the central bore of the cannula or within channels inside theouter walls of the device. Irrigation supply lines may, for example,junction with apertures and jets at their distal terminus positioned soas to direct a stream of such liquids and gasses towards the lens of anendoscopic camera, clearing the operative field (the area of thenotch(es) wherein branch arteries are severed/coagulated), and cleansingthe central bore of the harvesting cannula.

In certain preferred embodiments of the present invention, the outerwall—and most advantageously the inferior aspect thereof—of the cannulaincludes perforations so as to allow such irrigation to exit the centralbore of the cannula and form an aqueous layer or a carboxylated aqueouslayer about the cannula enhancing the ease of manipulating said device.In addition, preferred embodiments of the present invention include ameans for aspiration of the operative field and the area about thecannula. For example, in certain preferred embodiments of the presentinvention, the proximal terminus of the harvesting cannula provides ameans, such as an aperture or suction fitting, so as to provideaspiration of the central bore of the device. In addition, perforationsin the outer wall of the harvesting head allow such aspiration to beapplied to, so as to evacuate naturally occurring operate site fluids(such as blood) as well as fluids utilized for irrigation about thesurgical site.

The present invention also discloses a method of harvesting bloodvessels utilizing the vessel harvesting device disclosed herein. Inpracticing the method of the present invention, a vessel to be harvestedis first identified. Thereafter, and after the usual and appropriatesurgical site disinfection/preparation and administration of anesthesia,a skin incision is made in the vicinity of the distal extent of thegraft to be harvested. Thereafter, through careful blunt dissection, anarea circumferentially about the subject vessel is freed proximallyuntil the operative field about the most proximal extent of the graftdesired is reached. Thereafter, the distal terminus of the harvestingcannula is introduced through the distal skin incision and positioned sothat a portion of the vessel to be harvested—still fully connected tothe circulation, both proximally and distally—enters the cannula throughthe distal aperture and/or vessel alignment slot. Thereafter, the mainvessel capture and manipulation means is utilized, alone and incombination with gross cannula manipulation—to engage and capture thevessel to be harvested within the central bore of the cannula. Incertain preferred embodiments of the present invention the harvestingcannula itself, as described below, may be utilized to perform some orall of the blunt dissection.

In embodiments of the present invention wherein branch vessel capturenotches are provided and formed by and between the superior proximalterminus of the harvesting head and the distal terminus of the slidingoperation arm, the sliding operation arm is first placed in an open (oraft position). More specifically, prior to branch vessel capture, thesliding operation arm is placed in an aft position so as to open accessto the branch vessel capture notch formed by the space created betweenthe sliding arm and the harvesting head. Thereafter, the cannula isadvanced along the main vessel. The sliding operation arm may, from timeto time and as needed, be opened (moved to a more aft position) andclosed (moved to a more fore position) so as to facilitate capture andretention of branch vessels. Also, and as described in further detailbelow, in certain preferred embodiments of the present invention, vesselcoagulation and cutting means can be operated by “closing” the capturenotch by fore motion of the sliding operation arm.

As branch vessels are encountered and identified, the main vesselcapture and manipulation means is utilized to bias the main vessel so asto urge branch arteries into a position within the capture notches. Asdiscussed above, the location of the capture and manipulation meansprovides a downward, biasing force against the vessel so as tofacilitate entry into the capture notch. The cannula may also bemanipulated in a fore/aft as well as a rotating manner, so as to assistthe vessel capturing/manipulating means in positioning the branch vesseladjacent the most distal extent (or distal terminus) of the capturenotch opposite its origin at the alignment slot. Furthermore, inembodiments of the present invention wherein a retention gate(s) areutilized, such gate(s) also provide the same downward biasing force soas to facilitate lateral vessel capture and positioning within thenotches. In certain preferred embodiments of the present invention, theconcave portion of the outer cannula wall opposite the alignment slotprovides room for branch arteries that may arise from the posterior ofthe vessel to be harvested and prevents such posterior vessels frominterfering with cannula operation and advancement.

Thus positioned, the branch vessel is then separated from the mainvessel after hemostasis by severing means such as, for example, electrosurgery cutting tips, cutting blades, and/or a laser means locatedadjacent to the edges of the outer cannula wall defining the lateraledges of the capture notch. For example, opposite edges of the capturenotch may be provided with bipolar electro surgery tips wherein one edgeincludes an operating (active) tip/contact and the opposite end anantenna (neutral/ground) tip/contact. In addition, it certainembodiments, it may be preferred to utilize unipolar cautery with agrounding plate. In other embodiments, it may be preferred to utilizedcutting blades fabricated of, for example, surgical steel to free themain vessel to be harvested from the lateral branch captured within thenotch. Furthermore, the notch may include a laser or harmonic (e.g.,ultrasonic) cutting means to remove the lateral branch. However, it ispreferred that the at least one lateral branch capture notch includeselectro surgery tip(s) capable of delivering coagulating current so asto allow homeostasis on either side of the site of branch vesselsevering prior to such cleavage.

Certain preferred embodiments of the present invention utilize surgicalclips or coils as a means for achieving a similar hemostatic function.Surgical coils may be fabricated, for example, of a high elastic memorysurgical steel, or a surgical steel treated to exhibit such high elasticmemory as well as a high modulus of elasticity. In addition, the presentinvention contemplates other suitable surgical materials such as, forexample, a biocompatible plastic also formulated to provide high elasticmemory and a high modulus of elasticity.

The aforementioned surgical coils are selected for high elastic memoryso that, in the absence of external force, the elastic memory of saidcoils will cause them to assume a closed circular configuration.Furthermore, the coils are fabricated, configured and/or treated so thattheir closed circular configuration exhibits an inside diameter and amodulus of elasticity sufficient to cause the lumen of a branch vesselto which said coil is circumferentially applied—to close and remain so—.Such closure, of course, provides the desired hemostasis of branchvessels.

The above-described surgical coil, may be initially held in an openposition by, for example, channels or detents within a coil magazine.Upon operation of the harvester, the coils may be expelled from themagazine by extendable “fingers” and released upon a branch vessel. Inother preferred embodiments of the present invention, the entiremagazine may be urged forward via an operation rod for application ofthe coil to and about a branch vessel. Upon release, the coil returns toits circular configuration so as to surround and occlude a vessel towhich it is applied.

Certain preferred embodiments of the present invention may utilizesurgical clips fabricated from surgical steel, polycarbonate or anyother durable, biologically compatible material. (The terms“BIOLOGICALLY COMPATIBLE” and “SURGICALLY COMPATIBLE”, as utilizedwithin this specification and within the claims refer to materials whichare suitable for surgical placement in that they are amenable tosterilization and do not exhibit toxic, mutagenic or antigenicproperties which would cause injury to the patient in which suchmaterials are utilized.) In such instances, such clips may include ahinge means allowing an open configuration for “capturing” a branchvessel and a locking means, such as, for example, interlocking tineswhich allow the clip to be closed about and lock circumferentially abouta branch vessel. Such clips are also configured and adapted to obtain a“closed” configuration defining a diameter small enough to effectivelyocclude the lumen of a branch artery. In addition, the present inventioncontemplates the use of low memory surgical clips, made from low elasticmemory, biocompatible steel alloy, or steel alloy, especially treated toprovide low elastic memory. In such embodiments, the low memory surgicalclips, as discussed in more detail below, are crimped in place, about abranch vessel, by means, for example, of an anvil type device (similarto that utilized in a stapler). Such devices, discussed in more detailbelow, are configured to receive two open and leading ends of an open,low elastic memory coil and force such ends to approximate each otherand thereby close about a branch vessel.

As discussed above and below, certain preferred embodiments of theharvester of the present invention, especially configured and adaptedfor the use of surgical coils and/or clips as a means for occludingbranch vessels, may incorporate multi-clip or multi-coil magazines as ameans of enabling such harvesting devices to sever and occlude aplurality of lateral branch vessels—without necessitating removal of theharvester from the surgical site for reloading of such clips or coils—.Thus, embodiments of the present invention wherein such magazines areprovided may be utilized to sever and occlude multiple branch vesselswhile the device remains inserted and without the need for withdrawingthe harvester from the vessel being harvested thereby. Embodiments ofthe present invention may be configured so as to incorporate one or moreof such magazines depending upon the number of branch capture notchesconfigured therein. For example, in embodiments of the present inventionconfigured for and having only one branch vessel capture notch, only onesuch magazine is utilized. In embodiments of the present inventionconfigured and adapted to include a plurality of such branch vesselcapture notches, a plurality of magazines may also be utilized. In eachcase, each magazine is configured so as to enable delivery of a surgicalclip or surgical coil on either side of a point wherein said branchvessel is severed by the harvesting device. Harvesting devices of thepresent invention utilizing clips and/or coils to occlude branch vesselsadvantageously utilize a substantially heatless means, such as, forexample, a simple steel blade, so as to enable the device to harvestvessels without the production of heat. It is well known that theproduction of heat during vessel harvesting is detrimental to theviability of the graft. Thus, the present invention provides a bloodvessel harvester, and method for utilizing same, which enables theremoval of blood vessels for use in surgical graft techniques withoutthe generation of heat associated, for example, with electro or radiocautery techniques. More specifically, the present invention provides ablood vessel harvesting and method for utilizing same wherein device isutilized to sever branch vessels from a vessel to be harvested, withoutthe use of heat generating cutting and/or hemostatic means.

As utilized throughout this specification and throughout the claims, theterms “without the use of heat generating cutting and/or hemostaticmeans”, “without the use of heat generating means”, “without thegeneration of heat” and “heatless means” all refer to cutting and/orhemostatic means that do not depend upon heat to achieve function, donot function as a result of heat, and do not produce heat as asignificant byproduct. “Significant heat” and “significant amounts ofheat” as utilized herein is as the production of thermal energy capableof increasing the temperature of tissues in contact with cutting and/orhemostatic means above and beyond normal somatic temperatures. Forexample, electro cautery and radio cautery are both means of cuttingand/or achieving hemostasis that do significantly increase thetemperature of surrounding tissues. The application of clips and coilsto occlude, as well as the use of a metal blade to sever branch vessels,as described herein, are means which do not depend upon, utilize, orproduce as a byproduct of function significant heat energy.

In certain embodiments of the present invention wherein electro surgicaltips are utilized for hemostasis and lateral vessel occlusion, bothbi-polar and uni-polar current may be applied so as to provide bothcoagulating and cutting functions simply by altering the type of current(wave pattern) applied thereto.

It is still further preferred that two coagulation points be provided oneither side of vessel severance by means of, for example, two pairs ofelectro cautery tips, positioned on either side of a cutting meanscentered there between. For example, two pairs of bi polar electrosurgery tips/contacts (active and antenna/ground) may be positioned onopposite edges and adjacent to the lateral terminus of the capturenotch. A cutting means, such as, for example, a remotely controlledcutting blade may be advantageously located between the two pairs ofcoagulating tips or, in certain preferred embodiments, fore motion ofthe sliding operation arm is utilized to urge the cutting blade throughthe vessel. Therefore, when a branch vessel is identified by the remotecamera within the main vessel capture/manipulation means may be utilizedso as to bias the lateral branch into the capture notch adjacent to thecutting and hemostatic means therein. (Utilizing embodiments of thepresent invention comprised of non-conductive transparent plasticgreatly facilitates such visualization). The capture/manipulation meansis utilized to accurately position the branch arteries precisely at thecorrect cutting point. Thereafter two coagulation points, effectivelyoccluding the vessels are made close to its junction with the vessel tobe harvested. Alternatively, the device may be utilized to placesurgical clips on either side of the cutting point for hemostasis. Thecutting blade is then operated so as to cleave the branch vessel fromthe subject graft. Thus, the vessel is severed only after hemostasis isachieved. In certain preferred embodiments of the present invention,fore motion (or closure) of the sliding operation arm may be utilized toeffect the afore-mentioned severing of branch vessels (as described infurther detail, below).

After each branch vessel is removed from the main vessel, as describedabove, the cannula is advanced along the vessel, towards the proximalextent of the graft desired, capturing, coagulating (or clamping, e.g.Nitinol™ coils) and cleaving further branch vessels as they areencountered in a like manner. Irrigation, delivered within the cannulaand directed upon the surgical site where said cutting and coagulationare performed maintains a clear operative field. Furthermore, irrigantflow upon the lens of the camera is provided to keep same free ofobstructions. The cannula may be provided with a multiplicity ofperforations through the external wall, so as to provide furtherapplication of irrigant about the device so as to aid ease ofmanipulation as well as visualization. The cannula may also be providedwith a suction means within the central bore so as to removed irrigant,blood and debris from the operative site.

In certain preferred embodiments of the method of the present invention,a gaseous stream of CO₂, is combined with fluid irrigant such as, forexample, a saline solution. The inclusion of CO₂, has now been found tohave significant effects upon the release of Nitric Oxide (NO) from thevascular endothelium. Therefore, inclusion of agents that may eitherenhance or diminish the release or production of Nitric Oxide may beadded to, for example, a mister blower for application to the surgicalsite and the subject vessel to be harvested. More specifically, it hasbeen found that the controlled release of Nitric Oxide, tends to relaxthe endothelial lining and thereby significantly increased the viabilityof such vessels for use in grafting procedures such as, for example,coronary artery bypass. More specifically, it has now been discoveredthat by incorporating a flow of form about 2 L/Min (liters/minute) toabout 4 L/Min CO₂ the irrigant flow, a maximum beneficial effect isprovided.

Upon coagulation and separation of all branch vessels which junctionwith the desired length of vessel to be harvested, a second skinincision may be made in the vicinity of the proximal extent of thegraft. The proximal vessel transection may be made with the harvestingdevice, without need for a second incision. Alternatively, the vesselmay be clipped or coagulated, via an endoscopic procedure, without theuse of a second incision prior to transection. Thereafter, the vessel isseparated at its proximal and distal extent by the usual means.

Upon coagulation and separation of all branch vessels which junctionwith the desired length of vessel to be harvested, a second skinincision is made in the vicinity of the proximal extent of the graft.Thereafter, the vessel is separated at is proximal and distal extent bythe usual means.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of a portion of a preferred embodiment of thepresent invention.

FIG. 2 is a side view of the preferred embodiment illustrated in FIG. 1.

FIG. 3 is an isometric view of the preferred embodiment illustrated inFIG. 1.

FIG. 4 is a front view of the preferred embodiment illustrated in FIG. 1

FIG. 5 is a side view illustrating the entire length of the embodimentshown in FIG. 1.

FIG. 6 is a top view of a portion of an alternate preferred embodimentof the present invention.

FIG. 7 is an isometric view of a preferred embodiment of the presentinvention configured and adapted to include a clip cartridge.

FIG. 8 is a top view of a portion of the preferred embodimentillustrated in FIG. 7.

FIG. 9 is an isometric view of the portion of the preferred embodimentillustrated in FIG. 8

FIG. 10 is an isometric view of a portion of the preferred embodimentillustrated in FIG. 7.

FIG. 11 is an isometric view of a portion of the preferred embodimentillustrated in FIG. 10.

FIG. 12 illustrates a surgical coil suitable for use with the firstalternate preferred embodiment of the present invention.

FIG. 13 illustrates an isometric view surgical clip suitable for usewith the first alternate preferred embodiment of the present invention.

FIG. 14 is an isometric view of an example of the second alternatepreferred embodiment of the present invention.

FIG. 15 is an isometric view of the embodiment illustrated in FIG. 14.

FIG. 16 is an isometric view of a clip cartridge utilized in alternatepreferred embodiments of the present invention.

FIG. 17 illustrates an isometric view of a low memory surgical cliputilized in alternate preferred embodiments of the present invention.

DETAILED DESCRIPTION

FIG. 1-5 illustrate a harvesting cannula in accordance with a firstpreferred embodiment of the present invention. Harvesting cannula 2 isconfigured as an elongated, hollow, tubular structure. It is preferredthat the cannula is fabricated of a transparent, biocompatible,non-conductive material such as, for example, a plastic. The cannula hasan outer wall 4, a central bore 6, a distal terminus 8, a proximalterminus 10 and a longitudinal axis running from the proximal to distalterminus. Located adjacent the distal terminus, a harvesting head 12exhibits a greater diameter relative to the remainder of the cannula andthus provides an increased central bore area. It is preferred that theharvesting head demonstrate a rounded, for example, “egg shaped”contour, as demonstrated in FIGS. 1, 2 and 3 so as to assist theinstrument in effecting the above and below-described blunt dissectionof tissue about the vessel to be harvested. The tubular control segment23 is located contiguous and proximal to the harvesting head and isdiscussed in further detail, below. Portions of the outer walls of boththe harvesting head 12 and tubular control segment 23 (portions of saidsections located upon a superior surface 7 of the cannula opposite theinferior surface of the cannula 77) are comprised of a sliding operationarm 9. The sliding operation arm 9, as discussed above, is slidablyaffixed to a superior portion of the harvesting head and tubular controlsegment so as to enable fore/aft motion of the arm. Aft motion of thearm 3, motion of the arm towards to proximal terminus 10 of the cannula,(the “open” position) forms an opening in the outer walls of theharvesting head—the branch vessel capture notches 22 and 24. Fore motionof the sliding arm 5, motion of the arm towards the distal terminus ofthe cannula allows opposing walls of the capture notches to approximateeach other (the “closed” position) and enables, in certain preferredembodiments, the cauterization (in certain preferred embodiments,application of clips/coils) and sectioning of branch arteries alsodiscussed below. Therefore, a distal portion of the sliding operationarm completes the outer wall of superior portion of the harvesting headwhen the device is in the closed configuration.

In the first preferred embodiment of the present invention illustratedin FIGS. 1-5, the distal terminus 8 of the cannula is open so as to forma distal aperture 9 which is contiguous with the central bore 6. A mainvessel alignment slot 20 penetrating through the outer wall 4 of thecannula arises at its distal terminus from and communicates with thedistal aperture 9 of the cannula. Thus both the distal bore andalignment slot provide access to the central bore within the cannula. Inthe first preferred embodiment of the present invention, the main vesselalignment slot 20 is not aligned with the longitudinal axis of thecannula, but lies at an angular relationship with said axis. Utilizing askewed main vessel alignment slot further enhances the ability of theharvesting head to capture a vessel to be harvested. For example, if themain vessel alignment slot is aligned with the longitudinal axis of thecannula, the vessel might be easily displaced from the harvesting headas the cannula progressed along a vessel and was thus brought intoalignment with the vessel.

In the first preferred embodiment, the alignment slot extends from thedistal aperture, proximally along the outer wall of the harvestingcannula and terminates at a point 21 along the superior outer wall ofthe harvesting head formed by the sliding operation arm and in closeproximity to the proximal terminus of the harvesting head 25. Thus themain vessel alignment slot comprises an opening of the outer wall of thecannula extending from the distal aperture along the outer wall of theharvesting head and terminates at a distal portion of the slidingoperation arm 9.

In preferred embodiment illustrated in FIGS. 1-5, two branch vesselcapture notches 22 and 24 are formed by the aforementioned aft motion ofthe sliding operation arm 9. More specifically, aft motion 3 of the armopens a channel in the outer wall of a distal portion of the harvestinghead running in a generally circumferential direction about thelongitudinal axis of the cannula which communicates with both thecentral bore as well as the main vessel alignment slot. The notches thusformed are especially useful in the capture and severance of brancharteries. More specifically, when the sliding operation arm is urged inan aft direction, a channel—and, in regard to the first preferredembodiment of the present invention, 2 channels are formed—so as toprovide a pair of branch vessel capture notches 22 and 24. These notchesare advantageously provided with means therewithin for both cauterizingand severing branch vessels from a main vessel to be harvested. In thefirst preferred embodiment of the present invention illustrated in FIGS.1-5, electro-surgery points 30, 32, 34 and 36 located upon the proximalwalls of the branch vessel capture notches are oppositely charged(ground or active) as compared to electro-surgery contact points 38, 40,42 and 44 positioned within and upon the opposing distal notch walls.Therefore, when, as described below, branch vessels are maneuvered intothe capture notches, forward movement of the sliding operation armprovides direct contact between the electrodes (contact points) andbranch vessels. Activation of an electro-surgery unit connected to theafore-mentioned operating points, allows the surgeon to seal of suchvessels in to locations—one location more proximal to the main vesseland one location more distal. Alternatively, the afore-mentionedcontacts may, by means of forward motion of the sliding operation arm,be energized without need to independently activate an electro or radiocautery unit for each successive cautery application. In the firstpreferred embodiment of the present invention, a cutting blade 46 and 48located upon the notch walls and positioned between adjacent radio orelectro-surgery points allows the cannula to sever the branch vesselsbetween the cauterization points. Operation of the cutting blade may becontrolled by the closure (fore movement) of the sliding operation arm,or a separate control rod may be utilized to actuate the blades.

The harvesting cannula of the present invention includes a means forcapturing, retaining and manipulating a vessel to be harvested once thevessel has been introduced into the central bore of the harvesting headthrough the main vessel alignment slot. The vessel capture andmanipulation means may be advantageously comprised of a control rodpositioned and retained within the tubular control segment or thesliding control arm of the cannula. Such control rods include, at adistal terminus, a vessel capturing configuration designed to engage andhold a vessel for manipulation while still allowing proximal and distalmovement of the device along the vessel. At a proximal terminus, thecontrol rod includes a control means 52 so as to allow a surgeon torotate, extend and retracting the vessel capturing configuration. Forexample, while the central portion of the control rod lies in generalalignment with the longitudinal axis of the cannula, the distalterminus—the vessel capturing configuration—, may comprise a 90 degreebend in the rod thereafter presenting a “V” or “U” shaped opening ofsufficient size so as to engage and provide manipulation of the vessel.In such embodiments, rotation of the control rod allows an operator toalter the position of the main vessel within the harvesting head so asto facilitate capture of branch vessels within the branch vessel capturenotches.

In the first preferred embodiment of the present invention illustratedin FIGS. 1-5, control rod 50 includes dial 52 for rotation, extensionand retraction of the rod and a “pig tail” vessel capturingconfiguration 54 on the distal terminus thereof. Rotation of the controlrod 50 allows capture and manipulation of the vessel—and the sidebranches attached thereto—in regard to movement of the vessel insuperior 1, inferior 3 and lateral directions. Such control of the mainvessel and resultant control of branch vessels, facilitates placement ofbranches into the capture notches for cauterization and removal.

In a first alternative preferred embodiment of the present invention(illustrated in FIG. 6), a main vessel retention means comprisesretention gates 70 and 72. The retention gates, shown in a “closed”position, are utilized to ensure retention of the vessel to be harvestedwithin the central bore of the harvesting head. In addition, thelocation of the gates, just distal to the proximal terminus of the mainalignment slot, applies a strategic downward force upon the main vessel(towards the inferior surface of the cannula 77). The downward biasingforce is the result of i. the traction force already applied to thevessel due to its intact position, both proximally and distally withinthe circulatory conduit; and ii. the opposing retentive force applied tothe vessel to be harvested by the gates just prior to exit of the vesselfrom the proximal termini of the main alignment slot. As the cannula isadvanced, proximally along a vessel to be harvested, the biasing forcetends to urge branch vessels into the capture notches located, asdiscussed above, in close proximity with the capture gates. In the firstpreferred embodiment, the main vessel capture/manipulation means, e.g.,the control rod with pig tail also provide similar downward biasingforce and the resulting facilitation of branch vessel notch capture.However, embodiments incorporating the capture/manipulation meansdemonstrate the added utility of allowing increased control of vesselposition.

In the first preferred embodiment of the present invention, the tubularcontrol segment, provides a conduit and advantageously includes multiplechannels for an endoscopic camera, operating light, vessel control rod,irrigation and aspiration. The inferior surface 77 of the outer wall ofthe cannula may advantageously include a plurality of perforations 52allowing for irrigation and aspiration of both the operative site(within the harvesting head) as well as irrigation and aspiration of thefield about the cannula. It has now been discovered, as discussed infurther detail above, that by including a gaseous stream of CO₂ withinthe irrigant stream, the viability of the endothelium of vessels to beharvested may be greatly improved.

FIG. 4 is a cross sectional view of the first preferred embodiment.Control rod channel 55 provides a conduit and mounting means for controlrod 50. In addition, fiber optic endoscopic camera 56 (or endoscope) andlight 63 are located adjacent to irrigation channel 58 which providesboth irrigation of the operative field as well as a cleansing stream soas to keep the lens of the camera or endoscope free of debris.Aspiration channel 60 provides a conduit for the removal of irrigant,blood and other debris from the operative field.

It is highly advantageous to position the endoscopic camera lens withinthe tubular control segment, just proximal to, and directed towards thecentral bore of the harvesting head. Alternatively, such cameras may beplaced within the sliding control arm. As stated above, the relativelylarge central bore of the harvesting cannula provides a wide operativefield and excellent visualization. It is still further advantageous toutilize a lens with a sufficient field width so as to provide andgenerate an image providing a view of the central bore of the harvestinghead, the branch vessel capture notches and the main vessel alignmentslot. Such positioning and field performance of the endoscopic cameraand lens will therefore enable a surgeon the view 1. the vessel to beharvested; 2. the position of the vessel to be harvested during vesselintroduction into the harvesting head (during the rotation, extensionand retraction of the cannula by the surgeon as he or she attempts toposition the vessel within the main vessel alignment slot); 3.manipulation of the control rod and vessel capture/manipulation means(e.g. “pig tail”); 4. manipulation of branch vessels, after capture bythe capture control means, so as to position same within the branchvessel capture notches; 5. positioning the branch vessels within thebranch vessel capture notches so as to align said vessels with thecautery and cutting means; and 6. cauterization (or, in certainpreferred embodiments, the application of clips and/or coils) andsevering of branch vessels.

In practicing the method of the first preferred embodiment of thepresent invention, a vessel to be harvested is first identified. Forexample, it may be highly desirable to harvest the radial artery for usein bypass surgery. Therefore, after properly anesthetizing the patient,a skin incision is made at a point adjacent to the most distal extent ofthe vessel to be harvested after preparing the surgical site in theusual manner and after application of the usual disinfecting agents.Thereafter, a blunt dissection is carried out proximally, along thevessel sufficient so as to provide an ample operative field about thevessel. For this purpose, conventional surgical instruments may beutilized. However, the tapered “egg shaped” harvesting head of theembodiments of the present invention illustrated in the figures may alsobe utilized to provide such dissection. For this purpose, the harvestingcannula may be provided with a removable (such as “screw on” or “snapon”) domed shaped cap for occlusion of the distal aperture during thisinitial procedural step. After sufficient blunt dissection is performed,the vessel, such as, for example, the radial artery, remains intactwithout any severance of the vessel at either the proximal or distalextent of the graft. The vessel is purposefully allowed to remain intactin this manner so as to take advantage of the traction and stabilizationprovided by the connection of the vessel—at both ends of the graft—, tothe remainder of its course. The cannula is then positioned by thesurgeon, utilizing the endoscopic camera for guidance, so as to urge themost distal extent of the graft to be harvested—the main vessel—into themain vessel alignment slot 20. After positioning the main vessel withinthe slot, the surgeon then utilizes the main vessel capture andmanipulation means to engage and capture the vessel. For example, thesurgeon may utilize a control means to rotate, extend and retract the“pig tail” shaped distal terminus of the control rod so as to engage themain vessel.

As the cannula is advanced toward the proximal extent of the graft to beharvested, the main vessel passes through the distal aperture, into thecentral bore of the harvesting head, through the capturing configurationof the control rod (e.g. “pig tail”) and then exits the central bore ofthe harvesting head at the proximal terminus of the alignment slot.Thereafter, the vessel passes, substantially parallel to the long axisof the cannula against the devices outer surface. Upon encounteringlateral vessels (observed through the camera) the surgeon utilizes adial 50 or other control means to rotate extend and retract the controlrod so as to manipulate the vessel to be harvested so as to positionlateral branch vessels within the capture notches 22 and 24. The controlrod may be utilized in conjunction with manipulation of the entirecannula, or by itself, in order to position the branch vessels in such amanner as they are aligned with hemostatic and severing means. Thesurgeon may then advance the sliding operation arm forward, in a foredirection, so as to provide contact of opposing (ground and active)electro-surgical tips with each vessel on either side of the cuttingmeans. Upon contact with the branch vessels, current is applied to thebranch vessels so as to cauterize same at two points lateral to thepoint where the vessel is to be severed. Activation of theelectro-surgery unit providing the cauterizing wave form may be providedby sliding contacts within the cannula that close upon forward motion ofthe sliding operation arm completing a circuit or may optionally beprovided by a manually operated control switch mounted upon or separatefrom the tubular control segment.

After cauterization of a branch vessel, a cutting means, such as, forexample, a cutting electro-surgical current, laser, harmonic cutter orsharpened metal blade, located between the cauterization points, is usedto transect the branch vessel. In the first preferred embodiment of thepresent invention illustrated in FIGS. 1-5, sharpened steel edge 46 and48, located upon the notch walls and positioned between adjacentelectro-surgery points, allows the cannula to sever the branch vesselsbetween the cauterization points. Operation of the cutting blade may becontrolled by the closure (fore movement) of the sliding operation arm,or a separate control rod may be utilized to actuate the blades.

An alternate and preferred embodiment of the present invention,especially configured and adapted to utilize surgical clips and/or coilsis illustrated in FIGS. 7 through 11. More specifically, the preferredembodiment illustrated in FIGS. 7-11 is especially adapted to positionand affix surgical coils and/or surgical clips—which act as hemostaticmeans—for closing off the lumen of a branch vessel. The alternatepreferred embodiment illustrated in said figures contains surgical clipsor surgical coils within a magazine(s) (81 and 81′) located adjacentcapture notch(es) (22 and 24). Containment of a plurality of such coilsor clips enables the harvester to sever and occlude multiple branchvessels from a main vessel to be harvested without need to loadadditional clips or coils into the device or remove the device from thesurgical site.

In a similar manner as discussed above (in regard to the first preferredembodiment), during operation of the alternate preferred embodiment,manipulation of the entire harvester (grossly), and/or themanipulation/control means 54, is utilized to guide a branch vessel soas to lie within a desired capture notch 22, 24. Prior to severing saidbranch vessel from the main vessel, a pair of clips/coils are releasedfrom the magazine and affixed circumferentially about a branch vessel oneither side of a point along a branch vessel where the vessel is to besevered.

Control of the coil/clip magazine, cutting blade and all other harvesterfunctions are effected via controls located on the control handleillustrated in FIG. 10 and FIG. 11. For example, a right and left clipselector wheel (89 and 89′) located upon an upper portion of controlhousing 83 is utilized to select a particular pair of clips (or coils)to be dispensed from the clip magazines and applied, circumferentially,about a branch vessel prior to severance thereof (as discussed above andbelow in more detail). Trigger 91 is utilized to operate a blade 97 and97′ which are utilized to cut branch vessels from the main vessel duringharvesting operation. However, in certain preferred embodiments of thepresent invention, retraction of said trigger provides two separateoperation. Initial retraction of such trigger devices first releases aselected clip or coil (95 and 95′) and thereafter, upon furtherretraction of said trigger, the cutting blade 97 and 97′ are urgedforward so as to sever the branch vessel from the main vessel.Alternately, selector lever 93 may be utilized to alternate the functionof the trigger between clip/coil dispensing and blade operation.Magazine control lever 87 is utilized to select which magazine (of aright and left magazine) is activated for dispensing of a pair ofclips/coils. In certain embodiments of the present invention, lever 92is utilized to selectively control the application of suction andirrigation to the surgical site. Thumb wheel control 94 shown in FIG. 11is utilized to control the pig tail main vessel retainer manipulator 54discussed above and below.

FIG. 7 is a top forward view (isometric) of an alternate preferredembodiment of the present invention wherein clips or coils, positionedand held within magazines 81 and 81′ are utilized to hold and deliverysuch clips or coils circumferentially, about selected points of a branchvessel, on either side of a point wherein said vessel is to be severed.

FIG. 8 is a top view, and FIG. 9 is a forward lateral view (isometric),of a portion of the preferred embodiment of the present inventionillustrated by FIG. 7 showing the details of a clip/coil magazinesuitable for use with the alternate preferred embodiment of the presentinvention. Magazines 81 and 81′ are loaded with and carry two sectionsof surgical clips or surgical coils 95, 95′ on either side of space82/82′ therebetween utilized for operation of the surgical blade(s)97/97′). The blade(s) is utilized to cut a branch vessel from the mainvessel at a “severance point”, a term utilized throughout thisspecification and claims to refer to a point along a branch vessel wherebranch vessels, captured within the capture notch, are to be cut fromthe main vessel after the branch vessel has been homoeostaticallycrimped, on either side of said point, via the application of surgicalclips or coils released, positioned and applied by said device. It ispreferred that the severance point be no less than one millimeter fromthe anastomosis of each such branch vessel and the main vessel. Suchminimum distances allows for a sufficient length of branch vessel,remaining upon the main vessel after severance therefrom, to effectivelyretain a surgical claim or coil attached thereto.

As mentioned above, a pathway (82/82′) provided between the two sectionsof surgical clips allows for passage of blades 97 and 97′ which areutilized to sever branch vessels from the main vessel during harvestingprocedures. Clip detents 99 and 99′ selectively positioned via selectordials 89 and 89′ (discussed above) are utilized to selectively dispensea pair of clips or coils onto and circumferentially about branch vesselsduring harvesting operations. As discussed above, retraction of trigger91 dispenses selected coils or clips. More specifically, initialretraction of the trigger extends the detents forward so as to release aselected coil/clip onto and about a branch vessel. Thereafter, furtherretraction of the trigger results in extension of the aforementionedblades 97 and 97′ so as to sever the branch vessel from the main vessel.In examples of the alternate preferred embodiment incorporating morethan one clip/coil magazine and cutter, (such as shown in FIGS. 7-11)selector lever 87 is utilized to select which clip magazines/cutter isactuated by trigger operation. Since an effective hemostatic crimp isprovided by the placement of either surgical coils or clamps on eitherside of the cut provided by the blade(s), a heatless removal of branchvessels is provided by the first alternate preferred embodiment of thepresent invention.

An overview of the operation of the first alternate preferred embodimentmay be described as follows. (See FIGS. 7-11). FIG. 9 is intended tofurther convey the operation of the device disclosed herein byincorporating in said view illustration of a main vessel 107 and branchvessel 109 captured by the device.

The harvesting head 12 is utilized, in the same way described above inregard to the first and second preferred embodiments, so as to preformblunt dissection and capture a vessel to be harvested within the mainalignment slot 20 of the harvester head. A main vessel retention meanssuch as, for example, the pig tail device 54 described above, or any ofthe other retention/manipulation means discussed above, may be utilizedfor retaining the main vessel with the central bore of the harvestinghead—as well as manipulating the vessel so as to guide branch vesselsinto lateral capture notch(es) 22 and 24. In the alternate preferredembodiment of the present invention illustrated in FIGS. 7-11, twoclip/coil magazine units 81 and 81′ are located adjacent to the lateralcapture notches. The harvesting device may be utilized to manipulate thelateral vessels into the capture notch(es) 1. grossly, by manipulatingthe entire cannula via rotation, extension and retraction; an/or 2, viause of the vessel retention/manipulation means, so as to locateencountered branch vessels within the capture notches and within an area(roughly described as semi-circular) 98 defined by the open clips orcoils located within the clip magazines. The camera means, such as aminiature camera or endoscope coupled with a remote camera, describedabove, is advantageously utilized to observe the positions of saidvessels and assist placement within the capture notches.

An encountered branch vessel, visualized by the camera means, ispositioned within a capture notch. Thereafter the device may be grosslymanipulated, as discussed above, and the vessel capture/manipulationmeans may further assist manipulation of the main vessel so as toposition the branch vessel within the aforementioned semi-circular areadefined by the still open clips. Selector wheel 89 or 89′, dependingupon which notch is utilized to capture the branch vessel, is operatedto select an available pair of clips or coils for dispensing from themagazine adjacent the branch vessel encountered. Thereafter, trigger 91is utilized to urge a pair of clips or coils upon the branch vessels bymeans of the clip detents (99 and 99′) whose positions (and clipselection) were controlled by the selector wheel. When surgical coils,as illustrated in FIG. 12, are utilized, circumferential application andretention of coils is accomplished by selecting coils fabricated ofbiocompatible plastic (such as a polycarbonate) or surgical steelespecially formulated and/or treated to exhibit a high elastic memory.Such coils, having a high elastic memory which ordinarily causes them toclose down completely (so as to form a tight circle), can, for example,be held open in a “C-like” configuration by, for example, retaininggrooves or channels within the magazine. Upon being forced forward andout of the magazine by the detents, the coils are allowed to return totheir circular configuration and thus encircle and occlude a portion ofthe branch vessel upon which they are applied. As mentioned above, thecoils are also selected to exhibit a relatively high modulus ofelasticity so as to allow said clips to be held in an open position andeasily return to a closed position without deformation or breakage.

In embodiments of the present invention wherein surgical clips areutilized, such clips are likewise dispensed from the magazines forvessel occlusion. Such clips may be described as belonging to two types.The first type of surgical clip, a locking surgical clip, illustrated inFIG. 13, includes a hinge joint 100, as well as a locking means. Morespecifically, and in regard to the clip illustrated in FIG. 13, thelocking means is comprised of male latch and female receiver which, uponclip closure, mate and lock. Such clips are closed about a branch vesselvia extension from a clip magazine, as described above, and thereafter,closure via a clamping device, described in more detail below. A secondtype of surgical clip, a crimp clip, may advantageously be utilized withalternate preferred embodiments of the present invention. Such clips arefabricated of surgical steel exhibiting a low elastic memory. In suchembodiments, open crimp clips are initially contained within theafore-mentioned magazines in a roughly semi-circular “open”configuration. Crimp clips are forced forward during operation, in asimilar manner as described above in regard to the locking clip and thesurgical coil. However, upon full extension of the surgical crimp clip,a crimping device, (commonly referred to as an anvil) located on anopposite side of the capture notch from the magazine, is utilized tocrimp the low elastic memory clip about a branch vessel so as to closeoff the lumen thereof in much the same manner as a common staple isforced closed against a receiving plate (or anvil). In otherembodiments, a plier-like device, positioned above and below the clipmagazine, may also be utilized to further close the clip about a branchvessel.

Regardless as to whether a high memory coil, a locking clip or a crimpclip is utilized, such retention devices must be configured so as todefine a closed diameter which will effectively occlude the lumen ofbranch vessels. It is by this means that such clips/coils are utilizedto provide hemostasis, prior to vessel severance, without theapplication of heat.

After application of a pair of coils or clips to the branch vessel,knife blade 97 is advance forward, in a proximal direction so as tosever the branch vessel from the main vessel by means of trigger 91. Theblade utilized to sever the branch vessel may be, for example, a simple,non-vibrating steel blade or a harmonically (vibrating) blade.Embodiments of the present invention, utilizing a non-oscillating blade,simply include a means for extending the blade forward to sever branchvessels. Embodiments of the present invention utilizing harmonicallyoperated blades utilize the added energy of blade oscillation to enhancethe cutting action of the blade upon extension to and through a branchvessel. Thereafter, the harvester is further advanced until encounteringadditional branch vessels wherein the process is repeated. The mainvessel may thereafter be removed as described above. Thus, certainpreferred embodiments of the present invention utilize surgical clipscomprised of a low elastic memory surgical steel, or, a surgical steelformulated and/or treated to exhibit low elastic memory. Such clips aretherefore amenable to being easily formed (or crimped) about a branchvessel and remain in such hemostatic configuration without the need forminterlocking tines, groves or other mechanical means to maintain aclosed configuration.

FIGS. 14-17 illustrate a second alternate preferred embodiment of thepresent invention wherein the afore-mentioned low memory surgical steelclips are utilized for hemostasis. FIG. 14 illustrates a portion of thesecond alternate preferred embodiment including a harvesting head and adistal portion of the tubular control segment. A clip anvil 115, locatedadjacent the proximal lateral aspect of the harvesting head, isconfigured to receive a pair of low memory surgical clips 123 (see FIG.17). A plurality of surgical clips are conveniently stored, in clipmagazine 119 as illustrated in FIG. 16. In the example of the secondalternate preferred embodiments illustrated in FIGS. 14-17, a singlelateral branch capture notch is provided. In such embodiments, a singlemagazine port 125, within the tubular control segment, is provided so asto receive and retain a pair of clip magazines. Thus, in suchembodiments a pair of clip magazines is loaded into the magazine port125 and oriented so that a distal (or delivering) terminus 127 of themagazine is positioned approximately flush with the distal end of thetubular control segment. Also, the magazines are loaded into themagazine receiving port so that each of the cutting blade sides 131 ofthe magazines faces one another. The non-cutting blade sides of eachmagazine abuts opposite lateral walls 133/133′ of the port. A springslot 122 is provided for positioning a feed spring at the proximalterminus of each clip magazine.

The aforementioned cutting blade side of the magazines defines asubstantially rectangular space therebetween for operation and extensionof a blade for cutting lateral branch vessels, as discussed below.

Anvil 115 is especially configured and formed so as to define twoconverging clip receiving slots 116 and 116′. During operation of thesecond alternate preferred embodiment of the present invention, alateral branch vessel is encountered and guided into capture notch 114,as described above. Thereafter, utilizing, for example, a laprascope,the branch vessel is visualized and positioned so that it is adjacent tothe magazine port and between the upper and lower tines 140 (only onemagazine illustrated of two utilized) of the two lead surgical clipstherein. The clip magazines may then be urged forward (distally towardsthe harvesting heard so that a pair of lead surgical clips capture andextend past a lateral branch vessel. Thereafter, the tines of such clipsengage the converging clip receiving slots and are thereby closed aboutso as to provide hemostasis in regard to the branch vessel. Locatedbetween the clip receiving slots, a blade receiving slot 118 is providedfor receipt of a surgical cutting blade which is extended distally(forward) from between the aforementioned clip magazines and through thebranch vessel—after same has been hemostatically sealed on either sideof the severance point, as discussed above. Upon retraction of themagazines, new lead clips are urged forward by the clip springs.

The lead surgical clip 143 of the magazine illustrated in FIG. 16 (aswell as the adjacent magazine within the port which is not illustrated)is the clip which is adjacent the distal terminus of the magazine and,as such, the clip which is to be next dispensed thereby. Comparison ofthe clip magazine illustrated in FIG. 16 with the clip magazineillustrated in FIG. 8 immediately makes apparent a substantial decreasein the diameter of the harvester necessary in order to accommodate the“linear” design shown in FIG. 16. By utilizing magazines which align aplurality of clips substantially parallel to the longitudinal axis ofthe harvester, the overall diameter of the harvester may be greatlyreduced. More specifically, since the overall diameter of the harvesteris a limiting factor in regard to practical use of the device (insertionof the device into a necessarily limited surgical tissue space about avessel to be harvested) minimization of such diameters is a highlyadvantageous factor. Thus, by aligning clips in a pair of magazines,substantially parallel to the longitudinal axis of the harvester (asshown in FIG. 16), substantial reduction in the harvester diameter andentry into small tissue spaces is made possible.

As illustrated in FIG. 17, the low memory surgical clips 123 mayadvantageously include notches 151 so as to enhance engagement of, andretention of clips upon a branch vessel. Such notches may beincorporated into all of the above-mentioned coils and clips to providelike retention.

The terms and expressions which have been employed in the foregoingspecification and in the abstract are used therein as terms ofdescription and not limitation, and there is no intention, in the use ofsuch terms and expressions, of excluding equivalents of the featuresshown and described or portions thereof, it being recognized that thescope of the invention is defined and limited only by the followingclaims.

1. A blood vessel harvesting cannula having outer walls defining acentral bore therewithin, a proximal terminus, a distal terminus and alongitudinal axis, said cannula being comprised of: a harvesting head, atubular control segment and a control handle; a main vessel alignmentslot penetrating through a portion of the outer walls of the harvestinghead and tubular control segment, said slot beginning at the distalterminus of said cannula and ending within the outer wall of the tubularcontrol segment adjacent a distal terminus thereof, said main vesselalignment slot communicating with the central bore of the harvestingcannula; at least one branch vessel capture notch located between aportion of the outer walls of the cannula comprising the distal terminusof the tubular control segment and a superior portion of the harvestinghead adjacent thereto, wherein the at least one branch vessel capturenotch is circumferentially aligned relative to the longitudinal axis ofthe cannula and communicates with the central bore thereof and whereinthe branch vessel capture notch is lateral to and communicates with themain vessel alignment slot, and wherein the at least one branch vesselcapture notch includes therewithin surgical clips which provide aheatless means for achieving hemostasis and wherein the at least onebranch capture notch also includes a means for severance of branchvessels from a blood vessel to be harvested; and a main vessel retentionmeans for retaining a vessel to be harvested within the central bore ofthe harvesting head.
 2. The harvesting cannula of claim 1 wherein saidharvesting head demonstrates an elliptical shape.
 3. The blood vesselharvesting device of claim 1 wherein said main vessel alignment slot isconfigured in an angular, non-parallel relation relative to thelongitudinal axis of the device.
 4. The blood vessel harvesting deviceof claim 1 wherein said cannula includes a distal aperture.
 5. The bloodvessel harvesting device of claim 4 wherein said cannula furthercomprises a removable cap so as to enhance use of said device in bluntdissection.
 6. The blood vessel harvesting device of claim 1 wherein themain vessel alignment slot provides a substantially longitudinal openingwithin the outer wall of said cannula equal to or greater than a widthof a vessel to be harvested by said device.
 7. The harvesting cannula ofclaim 1 wherein said cannula includes two branch vessel capture notches.8. The harvesting cannula of claim 1 wherein said main vessel retentionmeans is configured to apply a biasing force to said vessel so as toassist placement of branch vessels arising therefrom into said at leastone branch vessel capture notch.
 9. The harvesting cannula of claim 1wherein said surgical clips are fabricated from a material selected fromthe group consisting of stainless steel and polycarbonate plastic. 10.The harvesting cannula of claim 1 wherein said surgical clips areselected to demonstrate a low elastic memory.
 11. The harvesting cannulaof claim 1 wherein said surgical clips include grooves for enhancingretention of said branch vessels.
 12. The harvesting cannula of claim 1wherein said surgical clips are contained within two sections of a clipmagazine, said magazine including a space between said two sections. 13.The harvesting cannula of claim 15 wherein a plurality of surgical clipsare sequentially positioned and aligned substantially parallel to thelongitudinal axis of the harvesting cannula within two magazines. 14.The harvesting cannula of claim 1 wherein each of said at least onebranch vessel capture notch includes at least one severing meansoperably mounted adjacent said notch and disposed to operate and extendthrough the space defined by and between the two sections of themagazine.
 15. The harvesting cannula of claim 14 wherein said severingmeans is selected from the group consisting of a non-vibrating steelblade and a harmonically operated blade.
 16. The harvesting cannula ofclaim 1 further comprising a main vessel retention and manipulationmeans thereby enabling said device to both retain and manipulate theposition of the vessel within the central bore of the cannula.
 17. Theharvesting cannula of claim 16 wherein said main vessel capture andmanipulation means comprises a control rod.
 18. The harvesting cannulaof claim 17 wherein the control rod is generally aligned with thelongitudinal axis of the cannula and includes, at a proximal terminusthereof, a means for controlling rod operation and at a distal terminus,a vessel engaging configuration enabling said rod to engage andmanipulate a main vessel's position within the central bore of thecannula.
 19. The harvesting cannula of claim 18 wherein said vesselengaging configuration is selected from the group consisting of a “V”shaped, “L” shaped and coil shaped distal termini.
 20. The harvestingcannula of claim 1 wherein the main vessel retention means comprisesretention gates.
 21. The harvesting cannula of claim 1 wherein saiddevice further comprises an endoscope and remote camera so as to enableobservation of capture and manipulation of a vessel to be harvestedwithin the cannula as well as manipulation and severing of branchvessels therefrom.
 22. The harvesting cannula of claim 1 wherein saidcannula further comprises a means of irrigating an operative field aboutsaid vessel to be harvested.
 23. The harvesting cannula of claim 22wherein said irrigation means is especially configured and adapted todelivers a saline solution to the operative field.
 24. The harvestingcannula of claim 22 wherein said irrigating means is especiallyconfigured and adapted to deliver an agent for enhancing the productionof nitric oxide by endothelial cells of the vessel to be harvested. 25.The harvesting cannula of claim 24 wherein the agent for enhancing theproduction of nitric oxide is CO₂.
 26. The harvesting cannula of claim25 wherein said irrigating means is configured and adapted to deliver aflow of about 2 liters/minute to about 4 liters/minute of CO₂ to theoperative field.
 27. The harvesting cannula of claim 1 wherein saiddevice also includes an aspiration means.
 28. The blood vesselharvesting device of claim 27 wherein said cannula includes a pluralityof aspiration and irrigation holes penetrating the outer walls of saidcannula.
 29. A blood vessel harvesting cannula having outer wallsdefining a central bore therewithin, a proximal terminus, a distalterminus and a longitudinal axis, said cannula being comprised of: aharvesting head, a tubular control segment and a control handle, whereina distal aperture is located at the distal terminus of said cannula andwherein the harvesting head demonstrates a greater diameter relative toother segments of the cannula; a main vessel alignment slot penetratingthrough outer walls of the harvesting head and tubular control segment,said slot beginning at the distal terminus of said cannula and endingwithin the outer wall of the tubular control segment adjacent a distalterminus thereof, said main vessel alignment slot communicating with thecentral bore of the harvesting cannula and wherein said main vesselalignment slot is configured in an angular, non-parallel relationrelative to the longitudinal axis of the device; at least one branchvessel capture notch located between outer walls of the cannulacomprising the distal terminus of the tubular control segment and asuperior portion of the harvesting head adjacent thereto, wherein thebranch vessel capture notch is circumferentially aligned in relation tothe longitudinal axis of the cannula and communicates with the centralbore thereof and is lateral to and continuous with the main vesselalignment slot, wherein a heatless branch vessel severing means isoperably mounted adjacent said at least one capture notch and disposedbetween two heatless hemostatic means comprising surgical clips; and amain vessel retention and manipulation means for retaining andmanipulating a vessel to be harvested within the main vessel alignmentslot and positioning lateral branch vessels within the at least onebranch vessel capture notch.
 30. The harvesting cannula of claim 29wherein said surgical clips are fabricated from a material selected fromthe group consisting of stainless steel and polycarbonate plastic. 31.The harvesting cannula of claim 29 wherein said surgical clips areselected to demonstrate a low elastic memory.
 32. The harvesting cannulaof claim 29 wherein said surgical clips include grooves for enhancingretention of said branch vessels.
 33. The harvesting cannula of claim 29wherein said surgical clips are contained within two sections of a clipmagazine, said magazine including a space between said two sections. 34.The harvesting cannula of claim 29 wherein said heatless severing meansis selected from the group consisting of a non-vibrating steel blade anda harmonically operated blade.
 35. The harvesting cannula of claim 29wherein said main vessel capture and manipulation means comprises acontrol rod.
 36. The harvesting cannula of claim 35 wherein the controlrod is generally aligned with the longitudinal axis of the cannula andincludes, at a proximal terminus thereof, a means for controlling rodoperation and at a distal terminus, a vessel engaging configurationenabling said rod to engage and manipulate a vessel's position withinthe central bore of the cannula.
 37. The harvesting cannula of claim 36wherein said vessel engaging configuration is selected from the groupconsisting of a “V” shaped, “L” shaped and coil shaped distal termini.38. The harvesting cannula of claim 29 wherein said device furthercomprises an endoscope and remote camera so as to enable observation ofcapture and manipulation of a main vessel to be harvested within thecannula as well as the manipulation and severing of branch vesselstherefrom.
 39. The harvesting cannula of claim 29 wherein said cannulafurther comprises a means of irrigating an operative field about saidvessel to be harvested.
 40. The harvesting cannula of claim 39 whereinsaid irrigation means is especially configured and adapted to delivers asaline solution to the operative field.
 41. The harvesting cannula ofclaim 39 wherein said irrigating means is especially configured andadapted to deliver an agent for enhancing the production of nitric oxideby endothelial cells of the vessel to be harvested.
 42. The harvestingcannula of claim 41 wherein the agent for enhancing the production ofnitric oxide is CO₂.
 43. The harvesting cannula of claim 42 wherein saidirrigating means is configured and adapted to deliver a flow of about 2liters/minute to about 4 liters/minute of CO₂ to the operative field.44. The harvesting cannula of claim 29 wherein said device also includesan aspiration means.
 45. The blood vessel harvesting device of claim 44wherein said cannula includes a plurality of aspiration and irrigationholes penetrating the outer walls of said cannula.